1. Field of the Invention
This invention relates generally to electronic circuits and, in particular, to current reference circuits.
2. Description of the Related Art
Current reference circuits are used in many different contexts. A current reference circuit provides a reference current to another circuit. Existing current reference circuits are not designed to provide one of multiple reference currents. Instead, they are intended to provide a single reference current. This limits the versatility of current reference circuits.
The present invention addresses this and other disadvantages of existing current reference circuits.
The present invention encompasses a programmable current reference circuit. The programmable current reference circuit includes a programmable resistance, where the programmable resistance is programmable to provide one of a plurality of resistances, where each of the plurality of resistances corresponds to one of a plurality of programmable current reference circuit outputs. In one embodiment, the programmable current reference circuit includes a current source coupled to the programmable resistance. In one embodiment, the plurality of programmable current reference circuit outputs includes a plurality of reference currents.
The present invention also encompasses a phase locked loop circuit. The phase locked loop circuit includes a signal generator and a programmable current reference circuit coupled to said signal generator, where the programmable current reference circuit is programmable to provide one of a plurality of programmable current reference circuit outputs. In one embodiment, the programmable current reference circuit comprises a current source and a programmable resistance coupled to the current source. In one embodiment, the programmable resistance is programmable to provide one of a plurality of resistances, each resistance of the plurality of resistances corresponding to one of the plurality of programmable current reference circuit outputs. In one embodiment, the plurality of programmable current reference circuit outputs includes a plurality of reference currents.
The present invention is explained in more detail below with reference to the drawings.